Clinical usefulness of newly developed prognostic predictive score for atezolizumab plus bevacizumab for hepatocellular carcinoma

Abstract Aims The aim of the present study was to elucidate detailed parameters for prediction of prognosis for patients with unresectable hepatocellular carcinoma (uHCC) receiving atezolizumab plus bevacizumab (Atez/Bev) treatment. Methods A total of 719 patients (males 577, median age 74 years) treated with Atez/Bev between September 2020 and January 2023 were enrolled. Factors related to overall survival (OS) were extracted and a prognostic scoring system based on hazard ratio (HR) was created. OS and progression‐free survival (PFS) were retrospectively examined, and the prognostic ability of the newly developed system was compared to CRAFITY score using concordance index (c‐index) and Akaike information criterion (AIC) results. Results Cox‐hazards multivariate analysis showed BCLC classification C/D (HR 1.4; 1 point), AFP ≥100 ng/mL (HR 1.4; 1 point), mALBI 2a (HR 1.7; 1 point), mALBI 2b/3 (HR 2.8; 2 points), and DCP ≥100 mAU/mL (HR 1.6; 1 point) as significant factors. The assigned points were added and used to develop the IMmunotherapy with AFP, BCLC staging, mALBI, and DCP evaluation (IMABALI‐De) scoring system. For IMABALI‐De scores of 0, 1, 2, 3, 4, and 5, OS was not applicable (NA), NA, 26.11, 18.79, 14.07, and 8.32 months, respectively (p < .001; AIC 2788.67, c‐index 0.699), while for CRAFITY scores of 0, 1, and 2, OS was 26.11, 20.29, and 11.32 months, respectively (p < .001; AIC 2864.54, c‐index 0.606). PFS periods for those IMABALI‐De scores were 21.75, 12.89, 9.18, 8.0, 5.0, and 3.75 months, respectively (p < .001; AIC 5203.32, c‐index 0.623) and for the CRAFITY scores were 10.32, 7.68, and 3.57 months, respectively (p < .001; AIC 5246.61, c‐index 0.574). As compared with CRAFITY score, IMABALI‐De score had better AIC and c‐index results for both OS and PFS. Conclusion The present results indicated that the proposed IMABALI‐De score may be favorable for predicting prognosis of uHCC patients receiving Atez/Bev therapy.


| INTRODUCTION
Hepatocellular carcinoma (HCC) has been reported to be the sixth most prevalent cancer type globally and third to fourth leading cause of cancer-related deaths worldwide. 1,2Recently, atezolizumab and bevacizumab (Atez/Bev), a recently developed immunotherapy method, received approval for treating unresectable HCC (uHCC)   and has been shown to be related to favorable therapeutic outcomes in real-world clinical practice. 3When possible, it is considered that Atez/Bev should be used to treat HCC patients classified as Barcelona Clinic Liver Cancer stage (BCLC)-C, while it has also been proposed as a systemic treatment regimen for earlier stage HCC (BCLC-B) patients showing transcatheter arterial chemoembolization (TACE) refractoriness status. 4,5Accordingly, an assessment tool for detailed prediction of prognosis and treatment decision making is needed to provide important clinical information following introduction of Atez/Bev therapy.Previous reports have shown that c-reactive protein (CRP) and alpha-fetoprotein (AFP) in immunotherapy (CRAFITY) score is a useful scoring system for predicting the prognosis of patients receiving Atez/Bev. 6,7On the other hand, the prognosis of HCC patients is known to be affected not only by tumor burden and malignant potential, 8 but also hepatic reserve function. 9The aim of the present study was to develop a method for detailed prediction of prognosis for HCC patients treated with Atez/ Bev based on clinical parameters related to malignancy potential, tumor burden, and hepatic function.

| MATERIALS AND METHODS
After excluding patients without data regarding CRP and/or tumor markers (AFP and/or des-γ-carboxy prothrombin [DCP]) (n = 36), 719 HCC patients treated with Atez/Bev between September 2020 and January 2023 at 25 different institutions were enrolled, after obtaining written informed consent.The treatment strategy with Atez/Bev was the same as previously reported 10 and is illustrated in Figure 1.The choice for its administration was made by the attending physician at each medical center.Patients were given intravenous Atez/Bev, comprised of Atez (1200 mg) and Bev (15 mg/kg of body weight), in accordance with the manufacturer's recommendations, every 3 weeks. 11Treatment was discontinued if a serious or unacceptable adverse event (AE) occurred, or when HCC progression was noted in clinical findings.The National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0, 12 was employed to assess AEs.The attending physician was responsible for determining the subsequent course of treatment following cessation of Atez/Bev.The present retrospective database analysis was conducted in compliance with the Japan Ministry of Health and Welfare Clinical Research Guidelines and Helsinki Declaration, following receipt of official approval.

| Upper gastrointestinal endoscopy prior to Atez/Bev therapy
In order to mitigate the risk of gastrointestinal bleeding as an AE associated with Atez/Bev, each patient underwent an upper gastrointestinal endoscopy examination within 6 months of commencing therapy.The findings were used to monitor the presence of esophago-gastric varices (EGV), which were categorized into three types; small straight (F1; Grade 1), enlarged tortuous (F2; Grade 2), or large coil-shaped (F3; Grade 3).In cases where bleeding was detected and with high-risk findings such as EGV grade 2 (F2) or higher, or positive for red-color sign, variceal ligation, or injection sclerotherapy was performed prior to commencing Atez/Bev therapy.

| Etiology of HCC
Using a Lumipulse HCV (FUJIREBIO Holdings, Inc., Tokyo Japan), positive anti-HCV findings were considered to indicate that HCC was due to HCV infection, whereas HCC due to a hepatitis B virus (HBV) infection was determined when the HBV surface antigen was positive using Lumipulse HBsAg-HQ (FUJIREBIO Holdings, Inc., Tokyo Japan).
Nucleotide analog administration, such as entecavir, tenofovir, or tenofovir alafenamide fumarate, was used to treat HBV-infected patients.For those without HBV or HCV infection but with a history of alcohol abuse (≥60 g/day), the underlying liver disease was attributed to alcohol. 13,14Patients with a documented history of autoimmune disease were ineligible for Atez/Bev treatment.

| Assessment of hepatic reserve function
Hepatic reserve function was assessed using Child-Pugh classification, 15 albumin-bilirubin (ALBI) score, 16,17 and modified ALBI grade (mALBI), for which ALBI grade 2 is divided into two subgrades (2a and 2b) with an ALBI score of À2.27 as the cut-off value. 9

| Diagnosis and evaluation of HCC stage
A diagnosis of HCC was based on the consensus statement of the Japan Society of Hepatology 18 and tumor staging on BCLC stage. 19ood test results showing increased AFP as well as contrastenhanced ultrasonography with perflubutane, 20 dynamic-CT, 21 magnetic resonance imaging, 22,23 and/or pathological findings during the clinical course were used for diagnosis.

| Evaluation of therapeutic efficacy of Atez/ Bev treatment
To evaluate therapeutic response, the response evaluation criteria in solid tumors (RECIST), version 1.1, 24 or modified RECIST (mRECIST) 25 was employed.Progression-free survival (PFS) was determined based on RECIST results.The response categories were progressive disease (PD), stable disease (SD), partial response (PR), and complete response (CR).The initial evaluation was performed approximately 6 weeks after commencing Atez/Bev treatment utilizing dynamic CT scanning.
Additional dynamic CT examinations were performed when necessary, even before the 6-week mark in some cases, depending on patient condition.Subsequent examinations were scheduled every 6 weeks following the initial assessment, with the time interval extended to 9-12 weeks after the first 6 months. 106 | Scoring for assessment of prognosis of uHCC patients treated with Atez/Bev CRAFITY score 6,7 and the newly developed IMmunotherapy with AFP, BCLC staging, mALBI and DCP evaluation (IMABALI-De) scoring system, the details of which are presented following, were used to assess the prognosis of patients with Atez/Bev.However, DCP is not available for clinical use in many regions outside of Japan, thus scoring using the IMABALI components with exclusion of DCP was also performed.

| Statistical analysis
For statistical analyses, Cox-hazard analysis, the Kaplan-Meier method, and log-rank test results were utilized.Log-rank test and Kaplan-Meier method results were used to assess overall survival (OS) and PFS following introduction of Atez/Bev.When a median value is shown, the interquartile range (IQR) is also presented.Statistical significance was determined when the p value was less than 0.05.
Akaike information criterion (AIC) and c-index results were used for comparisons between both prognostic predictive scores.Easy-R, version 1.61 (Saitama Medical Center, Jichi Medical University, Saitama, Japan), 26 a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria), was used to perform all statistical analyses.

| Clinical features of present cohort
The fundamental characteristics of the present patients are shown in off values for CRP (≥1.0 mg/dL), 6 AFP (≥100 ng/mL), 27 and DCP (≥100 mAU/mL). 27When the same analysis was performed without DCP, the results were not significantly different (Supplemental  2A).Interestingly, when OS was evaluated according to basal liver disease, IMABALI-De score showed a good ability to stratify the patients into viral and nonviral groups (Supplemental Figure 1), with similar results obtained for those with either first-or later-line treatment (Supplemental Figure 2).For patients with a CRAFITY score of  3A).Furthermore, when PFS was evaluated according to basal liver disease, IMABALI-De score showed good stratification for viral and nonviral (Supplemental Figure 4), with similar results obtained for the first-and later-line administration groups (Supplemental Figure 5).With CRAFITY scoring, mPFS was malignancy potential, that is, AFP and DCP, the same as used for CRAFITY score, while hepatic reserve function (mALBI 1, 2a, 2b, 3) is also included.That final parameter is considered to be the main reason for the superiority of IMABALI-De as compared with CRAFITY score found in this study.
A recent report noted that both overall response rate and PFS, which had a weighted Pearson correlation coefficient of 0.71 (95% Cl = 0.52-0.84)and 0.62 (95% Cl = 0.35-0.84),respectively, demonstrated a good correlation with OS. 28 However, post-progression treatments have also been shown to be significant prognostic factors in regard to immunotherapy for HCC. 29 16,17 Furthermore, the prognostic importance of ALBI grade has been elucidated for patients HCC undergoing immunotherapy. 29However, ALBI grade 2 covers a wide range of patients and considered to be a clinical issue.
We previously established a modified tool for assessment of hepatic function termed mALBI, in which the middle grade is divided into two sub-grades, 2a and 2b, based on a cut-off value of indocyanine green retention rate at 15 min (ICG-R15) of 30%. 96][37][38][39] In the same manner, hepatic function is also thought to be an important requirement for detailed assessment of the prognosis of HCC patients undergoing Atez/Bev therapy.Therefore, mALBI grade provides greater focus on hepatic function, along with tumor burden and HCC malignancy potential.
In addition to CRAFITY score, which focuses more on the malig- prognostic nutritional index, 41 and neo-GPS. 42The present study focused on hepatic function and tumor status, thus prognostic scores predicted by nutritional indicators were not included in the comparisons, though a study will soon be conducted that includes those various scores as well as the current scoring system to determine usefulness for predicting Atez/Bev prognosis after a sufficient observation period.It should be noted that in the present multivariate analysis results, CRP, unlike neo-GPS, did not remain a significant factor.
This may be because systemic drug therapy is being introduced relatively early in an increasing number of cases, such as those classified as BCLC-B.Therefore, it will be necessary to verify these results after incorporating a sufficient observation period in order to adequately consider this factor.In addition, specific cell subsets, such as exhausted CD8+ T and regulatory T cells, are preferentially enriched and potentially clonally expanded in HCC cases, unlike peripheral blood. 43Accordingly, peripheral blood fraction count alone is not necessarily a sufficient nutritional immune biomarker, indicating a need to establish a simple prognostic index combined with tumor burden, tumor malignant potential, and hepatic function.
In addition to the liver function and nutritional indices noted above, etiology, AFP reduction rate, macrovascular invasion, extrahepatic spread, AEs (skin reaction, liver damage, hypertension, proteinuria), serum interleukin-6, granulocytes expressing PD-1, vascular endothelial growth factor, angiopoietin-2, insulin-like growth factor-1, and circulating tumor DNA have been shown to be related to the outcome of Atez/Bev treatment. 44Biomarkers of immune checkpoint inhibitor therapy reported include PD-L1, ratio of tissue-resident memory T cells to depleted CD8+ T cells in the tumor microenvironment, regulatory T cells, 11-gene signature, high expression of CD274, T-effector signature, and intertumoral CD8+ T cell density. 45e present study aimed to construct a prognostic score that is easy to use in clinical practice and does not require examination of blood or tissue-based biomarkers.Nevertheless, the correlation of score obtained with the biomarkers presented here and other factors reported in the future will need to be examined.
Based on the clinical importance of hepatic reserve function, the present proposed scoring system is considered reasonable.Studies of BCLC staging and treatment strategy presented in 2022 recommend Atez/Bev or durvalumab plus tremelimumab (Dur/Tre) as a first-line systemic treatment option. 46,47The items in the IMABALI-De scoring system, that is, tumor burden, malignant potential, and hepatic reserve function, provide a versatile system that may also be prognostically useful in Dur/Tre treatment cases.If such usefulness is shown, then this system may also be helpful for selecting systemic pharmacotherapeutic agents for uHCC.
Although therapeutic response was found to be not significantly The present study has some limitations.First, while the results were obtained from multiple institutions, they were retrospectively analyzed, thus a study with a larger number of patients will be needed in the future for validation.Additionally, because there were missing data for some of the patients, including numbers of neutro- nant potential of HCC, mALBI grade and Child-Pugh score, indicators of hepatic function, were also examined in the present study and the results confirmed the usefulness of IMABALI-De score.Our research group has presented reports regarding the usefulness of nutritional indices as prognostic predictors of Atez/Bev, including NLR, 40 different among the IMABALI-De scores, except for a score of 5, PFS grading with IMABALI-De score showed good stratification, other than between the scores of 2 and 3. We previously reported that PFS shortens as mALBI grade worsens3 and the present resultsshowing a shorter duration of response as IMABALI-De score increased may be mainly related to hepatic reserve function.During the clinical course of HCC, assessment with the present scoring system should be considered so as to not to lose the opportunity for introduction of Atez/Bev for improving prognosis within a short time after BCLC-B status or greater is noted.While systemic therapy is the only treatment available for BCLC-C HCC, TACE is a major option for BCLC-B HCC as well as systemic therapy.Atez/ Bev has been reported to provide clinical benefits for TACE unsuitable patients with BCLC-B HCC beyond the up to seven criteria.48Therefore, clinicians should consider switching to Atez/Bev as soon as possible, especially when the IMABALI-De score is low, in order to obtain greater therapeutic benefit.Accordingly, the present IMABALI-De scoring system might be useful as an indicator for switching treatment in BCLC-B HCC patients who have initiated TACE before prediction of poor prognostic benefit of treatment with Atez/Bev.
phils and lymphocyte cells, comparisons with previously reported prognostic indicators were not performed.A prospective study that uses long-term follow-up findings will be needed to confirm the usefulness of the present IMABALI-De scoring system and also compare it with other prognostic indicators.It will also be important to continue to search for common clinical factors specific to combined immunotherapy treatment with Atez/Bev.In conclusion, the proposed IMABALI-De score, which consists of common clinical items including mALBI grade, is considered to have a good prognostic predictive ability for uHCC patients receiving treatment with Atez/Bev.With considerations based on individual case factors, introduction of Atez/Bev at the lowest possible IMABALI-De score is recommended for improvement of prognosis.